Rectal cancer chemotherapy with strong vomiting is treated according to different reasons. If the gastrointestinal reaction is caused by chemotherapeutic drugs, antiemetic drugs, dopamine receptor antagonist such as metoclopramide, 5-HT3 receptor antagonist such as tropisetron, ondansetron, granisetron and so on can be applied, and corticosteroids such as dexamethasone can be applied. Other causes of vomiting, such as intestinal obstruction, require active treatment of the primary disease. 1. Treatment of chemotherapy-induced vomiting: (1) Dopamine receptor antagonists such as metoclopramide, through the inhibition of the neurotransmitter or receptor mediating vomiting to achieve the effect of inhibiting vomiting, if there is still severe vomiting reaction, then the dose of the drug can be adjusted or change the drug and so on. (2) 5-HT3 receptor antagonists such as tropisetron, ondansetron, granisetron, etc., the second generation is palonosetron, the main adverse effects are headache, constipation, dizziness, diarrhea, fatigue and abdominal pain. (3) Corticosteroids such as dexamethasone, etc. The combination of corticosteroids and 5HT3 can improve the control rate of acute vomiting, and the adverse effects are fluid retention, mood changes, insomnia, gastric ulcers and elevated blood glucose. If there is still severe vomiting reaction, then the drug dose can be adjusted or change the drug, etc. 2. Vomiting caused by other reasons such as intestinal obstruction: Intestinal obstruction is treated according to the cause, such as gastrointestinal decompression, rehydration supportive therapy, enema and surgery to remove the obstruction, and surgical methods include intestinal resection, intestinal short-circuit anastomosis surgery, enterostomy surgery and so on. Rectal cancer chemotherapy vomiting is strong, it is recommended to go to the hospital in time, clear diagnosis and treatment, so as not to delay the condition.